混凝土静动力破坏过程的CT细观试验研究  

Study on the CT meso-test experiment of static and dynamic failure processes of concrete

作　　者：党发宁[1] 雷光宇[1] 丁卫华[1] 马怀发[2] 陈厚群[2] 

机构地区：[1]西安理工大学岩土工程研究所,西安710048 [2]中国水利水电科学研究院工程抗震研究中心,北京100048

出　　处：《水力发电学报》2015年第1期189-196,共8页Journal of Hydroelectric Engineering

基　　金：国家自然科学基金(50879069;51409228);水利部公益性行业科研专项(201201053-03);陕西省黄土力学与工程重点实验室重点科研计划项目(09JS103);西安理工大学博士基金(106-211107)

摘　　要：X射线CT是无损探测混凝土内部细观裂纹萌生、扩展、贯通的有效手段。本文利用自行研发的CT试验加载系统,分别对静力和动力作用下混凝土细观破裂过程进行实时CT扫描观测,得出试件裂纹的开裂、扩展、贯通的全过程CT图像。通过对试验成果的分析,研究试件在静力和动力作用下的破坏过程,根据荷载位移曲线,得出试件的破坏强度,从CT图像和CT数发现静力加载时破坏面追随结构软弱面向前发展,最后贯通试件破坏;动力加载作用下细观裂纹生成和发展速度快,裂纹追随能量释放最快路径发展,穿过骨料现象增多,强度得到充分发挥,导致动态强度增大。从细观上反映了混凝土静力和动力破损的特点。为研究混凝土材料不同应力状态时的强度差异提供了一定的试验依据。X-ray CT is an effective nondestructive means to detect initiation, extension and breakthrough of the internal micro cracks in concrete. Using a self-made CT test system, CT images have been obtained for showing the whole process of cracking, crack extension and breakthrough in specimens, via real-time CT scan observation on the microscopic failure process of concrete specimens under static and dynamic loads. Analysis of these images revealed the details of static and dynamic failures, and destructive strength of the specimen is obtained by using the load-displacement curve. CT images and CT numbers show that under static load, cracks develop and extend following the structural weak surface and finally breakthrough in specimen failure. Under dynamic load, the micro cracks generate and develop faster and they follow the path of fastest energy release, causing more cracking of aggregate and hence leading to a full play of the material strength and a higher dynamic strength. This study provides microscopic features of static and dynamic damage of concrete and lays a basis for further study on strength theory of concrete material.

关 键 词：水工材料 CT图像 CT数 混凝土 动力荷载 

分 类 号：TV41[水利工程—水工结构工程]